The objectives are to further develop instrumentation and cytochemical techniques for directed automated high speed sorting of functionally different human and other mammalian cells. Our present fluorescence activated cell sorter can now separate cells at rates exceeding 5,000 per second into fractions determined by simultaneous measurement of fluorescence (down to 5,000 molecules of fluorescein per cell) and low angle light scattering. We plan to expand our data processing capability by integrating a small on line computer with the instrument. Programs will be developed to monitor and display all characteristics, defined by two or more parameters, and to manipulate and store this data. We will also make further studies on the light scattering characteristics of cells to extend the usefulness of light scattering as a separation parameter. Applications include studies of the immune system, cell genetics and clinical immunology and hematology.